Fig. 5.

NEM labeling stabilizes tau K18 oligomers in their globular conformation. NEM-labeled and unlabeled control tau K18 samples were each incubated with heparin at 37 °C for 48 h, and aliquots analyzed using negative-stain TEM. (A) Representative TEM micrographs of NEM-labeled tau K18 aggregates. The globular nature of these non-fibrillar aggregates in A(i) and A(ii) suggests oligomer stabilization. (B) Representative TEM micrographs of endpoint samples demonstrating the aggregation of unlabeled tau K18 into oligomers, protomers, short and mature fibrils. n = 2, with images taken from at least 5 different areas of each grid. Scale bars = 100 nm for all images.